With mods such as Headers, exhaust & intake, is there any benefit from running spark plugs that are one step colder, or is it best to stay with the stock heat range plug?

 

I am also curious about this.

 

Apparently no one knows?

I don't think running one step colder plug will harm anything, as long as the plugs are not fouling.

 

I found this thread: https://my350z.com/forum/showthread....ht=spark+plugs

But it sounds pretty inconclusive....

 

I was running 1 step colder Denso Iridiums, and they worked just fine. However, my car broke down last week, so I Checked my plugs, and they look like I am running lean. I think that I may be maxed out on N/A mods for now. The combiantion of Nismo Headers, Injen Exhaust, the JWT pop charger, Crawford Plenum, and Crawford cats seems to have my car running quite lean. Either that, or I have a manifold leak that is causing my plugs to be whiter than snow.

F.Y.I. to everyone, my car died on me last week in the middle of an intersection and then would not crank back up till the next day when I reset the ECU and put the stock plenum, intake, and stock plugs back on the car. For some unknown reason it took this combo to get my car running again. When I checked my plugs they were fried, but not to the point where I created any engine damage. I wonder what would have happended running the stock plugs? I am now going back to NGK stock heat range irridium plugs, and will have to install my Apexi fuel managment computer before I can run my car with all these mods. My car is now running great with just the Headers and exhaust.

from one uki to another.